While some improvements in the health of the United States (US) population have occurred over time, the persistence of disparities between groups, namely racial/ethnic or socioeconomic groups, indicates that such improvement has been uneven. Although these disparities have been documented over the years and some studies have attempted to examine trends over time, it has been challenging to estimate the magnitude and direction of these disparities across groups due to the lack of a uniform or standard methodology to measure health disparities and their trends across time. Oral health disparities are not an exception to this challenge. The goal of this proposal is to develop and test a methodology to assess oral health disparities in dental caries and periodontal diseases across populations over time. In order to accomplish this goal, we propose the following two specific aims: Aim 1: Use data from NHANES III to develop sensitive methods to measure disparities in dental caries and periodontal disease in the US population accounting for the difference in case definitions across studies. These methods will be developed considering and accounting for: a) the distribution of disease in the population by age, gender, race/ethnicity and socioeconomic position (SEP) indicators; b) the selection of the best reference group; and c) the comparison of results obtained using relative versus absolute measures of disease. Aim 2: Use data from NHANES 1999-2002 to test the measures developed in Aim 1 to assess oral health disparities in dental caries and periodontal disease. Testing the validity and reliability of the developed methodology in Aim 1 using the NHANES 1999-2002 data will allow us to provide guidelines and recommendations for the use of uniform and standardized measures to document the existing oral health disparities in studies at the local and national levels across groups of the population over time. This proposal's aims are consistent with the NIDCR Strategic Plan's Crosscutting Areas-Health Disparities and Data acquisition and Analysis-and the Healthy People 2010's goal of eliminating health disparities among segment of the US population. Specifically, accomplishing this proposed study's aims has the potential to contribute to our understanding of oral health disparities in the US; to provide the tools to gauge the magnitude and direction of oral health disparities using uniform measures in studies at the local and national levels; and to recommend guidelines for oral health disparity comparisons across studies and populations over time. Finally, the developed measures have the potential to be used to measure health disparities related to age, gender, race/ethnicity and socioeconomic position on other oral health outcomes and health outcomes in general. [unreadable] [unreadable] [unreadable]